Apparatus for eliminating air flow through fluid meters



Oct. 8, 1968 w. F. BERCK 3,404,567

7 APPARATUS FOR ELIMINATING AIR FLOW THROUGH FLUID METERS Filed June 13,1967 3 Sheets-Sheet 1 INVENTOR.

ATTORNEYS WILLIAM F. BERCK Oct. 8, 1968 w. F. BERCK 3,404,567

APPARATUS FOR ELIMINATING AIR FLOW THROUGH FLUID METERS Filed June 13,1967 5 Sheets-Sheet 2 INVENTOR.

WILLIAM F. BERCK ATTORNEYS Oct. 8, 1968 w. F. BERCK 3,404,567

APPARATUS FOR ELIMINATING AIR FLOW THROUGH FLUID METERS Filed June 13,1967 3 Sheets-Sheet 3 42 32 "*PRESSURIZED AIR SUPPLY FIG. 3 INVENTOR.

WILLIAM F. BERCK BY 7% W W./

ATTORNEYS U ited Sweet 1 Q -'3,404,567 t APPARATUS FOR ELIMINATING AIRFLOW 'THROUGH FLUID -METERS William F. Berck, Hayward, Califi, assiguorto Rockwell Manufacturing Company, Statesboro, Ga'.,.a corporation ofPennsylvania Continuation-impart of application Ser. No. 337,450, Jan.13, 1064. This application June 13, 1967, Ser.

No. 645,838 a 3 Claims. or. 73-200 ABSTRACT OF THE DISCLOSURE Thisapplication is a continuation-in-part of my copendingapplication, Ser.No. 337,450, filed Jan. 13, 1964, now abandoned. g This inventiongenerally relates to fluid metering systems and particularly toapparatus employed therewith for eliminating entrained air or gases fromthe metered flow line as to prevent false registration.

Apparatus of the general kind herein described has also been thesubjectm'atter of many previous inventions, iricluding my issued PatentsNos. 3,021,684, 3,040- 573 and 3,040,574, which patents depend upon theuse of a pump in ametereing system to provide the power for moving thefluid therethrough. The apparatus and methods described in my abovementioned patents however, cannot be used in gravity fed meteringsystems where the liquidmust'flow without benefit of a pump and wherethe only moving force is derived from the limited pressureof thepositive head on the upstream side of the meter. and/or the negativehead of liquid downstream ofthe meter. The present invention isparticularly directed tr) apparatus that may be used with this lattertype of metering system'for eliminating accumulated air that is trappedin a collecting chamber, although this apparatus may also beused with apump-pressurized systern.

One typical use for a gravity-type metering system is in connection withmobile tanks or delivery vehicles. Such vehicles containlone or morecompartments from which fluidis"delivered bygrav ity through a meter anddischarged frbm a delivery hose into a fill pipe of an undergroundstorage tank. A control valve for shutting off the fluid flow maybeprovided on, the discharge side of the meter, andin many instances thedelively hose is coupled to the fill pipe of the underground storagetank in a leakptoof' manner so thatthe' metering system develops anegative head of pressure on the downstream side of the meter thatextends'to the lower end of the fill pipe, near the bottom of thestorage tank. Alternatively, the metering system for the deliveryvehicle may use a downspout connected to the discharge end of the hosewithout forming a tight coupling'with the fill pipe. In this instance,the negative pressure head is determined by Patented Oct. 8, 1968thedownstream side of the meter to produce a negative liquid head.However, as the hose and fill pipe on the downstream side of the meterbegin to fill, a negative head is developed by the gravity force of thefluid therein, thereby increasing the rate of fluid flow through themeter. The negative liquid head added to the positive liquid headproduces a total gravity force which may result in a very high rate offlow and which is not obtained by a positive liquid head alone. Althoughthe maximum rate of fluid flow occurs shortly after the full negativeliquid head is developed, since the positive liquid head continuallydiminishes, the negative liquid head is usually capable of maintainingthe meter speed at a relatively high level.

As a vehicle compartment approaches empty, a vortex will normally beformed around the compartments outlet or sump. This vortex tends to drawair into the fluid where it becomes entrained. Although devices known asvortex breakers are employed, small amounts of air may neverthelessbecome entrained in the fluid, and unless eliminated will pass throughthe meter producing an error in measurement. Another type of meteringerror may be introduced where the compartment of a delivery vehicle hasbeen emptied and the lines from the sump to the meter are partiallyfilled with air. Refilling the tank compartment may trap large pocketsof air in the metering line and this air, which may represent aconsiderable volume, will then be washed through the meter when thecontrol valve is opened for making the next delivery.

The above difficulty in efiecting an accurate recording of metered flowshas always been present in making a gravity-type delivery from a tanktruck. In former years, the rates of flow were quite low and aconventional air separator with float-operated air release valve couldbe used to eliminate entrained air and prevent entrapment of the air inthe metering flow line. However, present day requirements demand higherrates of fluid delivery, and speeds of 350 to 450 gallons a minute arenow being achieved with a gravity delivery. At these relatively highrates of flow, it is impossible to provide an air separator ofreasonable size that may be installed on a tank truck and yet beeffective. The present invention, therefore, involves a novel means forpreventing the measurement of air in a fluid metering system, especiallysystems where the fluid is moved by gravity.

In brief, the present invention comprises apparatus for channeling, bythe use of an air-powered servo system. and through a bypass line aroundthe meter, bubbles of just enough accumulated air to disrupt. thenegative pressure head and momentarily retard or impede the liquid flowthrough the meter, followed by immediate re-establishment of full flow.For this purpose, an actuating mechanism comprising a spring bias and anair-operated cylinder are provided, together with a pressurized airsupply and a float-operated control valve. The float, which operates thecontrol valve, rides upon the surface of a conventional butcomparatively small air collection chamber disposed on the upstream sideof the meter; and when the liquid level is lowered by a just sutficientaccumulation of air or other gas to break the siphon downstream, thecontrol valve is operated to connect the air cylinder to the air supply,closing a shut-off valve in the metering flow line while simultaneouslyopening a normally closed valve in the bypass line, which extends between theair collection chamber and the discharge side of the meter.

One principal object of this invention is, therefore, to provide a novelapparatus effective at high flow rates for eliminating entrained air andventing such air to the downstream side of a meter.

Another object is to provide apparatus of the kind described in ametering system having a flow rate that is essentially determined by thenegative liquid head on the downstream side of a meter, and where theventing of accumulated air to the discharge side of the meter will bejust enough to break the siphon elfect of the negative liquid head,followed by re-establishment of full flow.

It is yet another object of this invention to provide metering apparatusof the kind described which may utilize the standard air-brake pressuresupply conventional to most tank delivery vehicles for closing a shutoffvalve in a metering flow line while simultaneously venting accumulatedamounts of air to the discharge side of a flow meter.

Other objects of this invention will become apparent in view of thefollowing detailed description and the accompanying drawings.

In the drawings forming a part of this application and in which likeparts are identified by like reference numerals throughout the same,

FIG. 1 is a side elevation of a delivery vehicle with certain partsbroken away and shown in section, wherein fluid stored within one ofseveral compartments of the delivery vehicle is being discharged througha fill pipe into an underground storage tank;

FIG. 2 is a detail and elevation of the metering apparatus used with thevehicle, including a gas collecting chamber and related apparatusemployed therewith;

FIG. 3 is an enlarged section taken essentially along lines 3-3 of FIG.2;

FIG. 4 is an enlarged section of the control valve taken on lines 44 ofFIG. 3, showing its position when the air collection chamber is filledwith liquid; and

FIG. 5 is another section of the control valve showing an alternateposition of the valve when the collection chamber has been substantiallyfilled with air or other as. g Referring to FIG. 1 of the drawings,there is shown a preferred embodiment of the invention in a deliveryvehicle having a plurality of liquid compartments 11, 12 and 13 that maybe selectively and alternately connected to a discharge flow line 14through an air collection chamber 15 and metering apparatus 16. Thevalve system which is used for making selective connection of chambers11, 12 and 13 to the air collection chamber 15, while not being shown,is of conventional design and forms no part of the present invention. Apipe connection 17, which joins the discharge end of line 14 to the fillpipe 18 of an underground storage tank 19, is essentially air tight, asare all fluid connections intermediate storage chambers 11, 12 or 13 andflow line 14. Thus, once fluid has been conducted through flow line 14and introduced into fill pipe 18, there will be a siphon pressuredeveloped by the negaitve head on the discharge side of meter 16.

This invention is more particularly directed to the apparatus shown inFIGS. 2-5. In particular, a butterfly valve 20 is disposed on theupstream side of meter 16 in the connecting passageway between aircollecting chamber 15 and the meter. Valve 20 is actuated between openand closed positions by the reciprocating movement of a link 21, saidlink being pin connected to a crank arm 22 secured to the pivotedsupport shaft 23 of butterfly valve 20. Link 21 connects to a piston rod24 that is reciprocally mounted to an air cylinder 25, and beingsupported by an end plate 26 and an upper boss 27. Plate 26 is formedwith a breather opening 28 that allows air to be taken in or expelledfrom cylinder 24 as a piston member 29 secured to piston rod 24 isreciprocated therewithin. A pair of screws 30 are employed to secure endplate 26 to the lower end of cylinder 24; and conventional type O-ringseals are provided within the upper end of boss 27, within the shaftopening of piston 29, and peripherally of said piston to define a fluidtight pressure chamber 31 within the upper end of cylinder 25.

A pressurized air supply 32 is adapted to be connected with chamber 31through a passageway 33, a control valve 34 and a pressure line 35. Forpurposes of this invention, conventional air-brake pressure supplies maybe used as the air supply 32.' Valve 34 is float-operated in a mannerwhich will be more particularly described in connection with FIGS. 4 and5 for applying pressure into chamber 31 or for venting-said chamber toan exhaust port. .3 z Although air collection chamber 15.-is essentiallycon- '-ventional,having an inlet openingi36 and a strainer 37 throughwhichall fluid must pass before-it is-'discharged around valve 20, theinterior of air cdllectifig chamber 15 communicates through opening 38with the interior of a bowl 39, formed integrally with boss 27 ofcylinder 25. Therefore, any air collecting in chamber 15 is free to passthrough opening 38 into the inner region of bowl 39, and depending uponthe position of a valve member 40 secured to the upper end of piston rod24, any and all air within chamber 15 may be discharged into a bypassline 41, including a connector piece 42. With reference to FIG. 3, valve40 is urged into engagement with the valve seat of bypass connectorpiece 42 by a helical spring 43, said spring being coaxial with boss 27and piston rod 24.

Referring to FIGS. 4 and 5, control valve 34 is operated by aconventional float 44 disposed within air collection chamber 15. Float44 rides on the surface of the liquid contained within the chamber whilebeing'attached to the extended end of. a pivoted float arm 45, saidfloat arm being secured to a lever 46 that is pivoted by a pin 47 from asupport stud 48.

Control valve 34 comprises a housing 50 having' a threaded inlet port 51which connects an axial passageway 52 to the pressure air supply 32. Anoutlet port 53 communicates with passage 33 for transmitting airpressure to chamber 31 of air cylinder 25. Housing 50 further providesan exhaust port 54; and a sliding valve rod 55 disposed withinpassageway 52 provides alternate communication either between inlet 51and outlet 53, or between outlet 53 and exhaust port 54. O -ring seals56, 57 and 58 are provided within the passageway '52 to effect a sealagainst surfaces of the rod 55. However, only 0- ring 58 engages rod 55at all times; seals 56 and 57, by reason of the necked portion 55a ofthe slide rod, provide alternate communication between port 53 and inletand exhaust ports 51 and 54, respectively;

An inspection of FIG. 5 will show that uponleftward movement of sliderod 55 from the position of FIG. 5, communication between port 53 andport 51 will be cut off almost immediately, whereas communicationbetween port 53 and port 54 will not be'established until a quitesubstantial amount of leftward movement has taken place. The same thingin reverse is done during rightward movement of the rod 55 from theposition of FIG. 4.

This lost motion travel of rod 55 during which port 53 is not incommunication with either of ports 51 and 54 corresponds to a floattravel just sufiicient to accumulate enough air so that the air bubblereleased between the opening of bypass valve 40 (by communicationbetween ports 53 and 51) and its reclosing (by communication betweenports 53 and 54) is of sutficient size to break the siphon.

Likewise, once the bypass valve 40 has closed and the siphon has beenre-established, valve 40 cannot bereopened by the float until an amountof air sufficient to again break the siphon has accumulated'in thecollection chamber. In a typical installation, this amount may be on theorder of 1 /2 pints; and the entire chamber capacity need not besubstantially greater. V

Slide rod 55 is provided with a transverse groove 59 in its extended endadjacent lever 46,and a stud 60 mounted to lever 46 is received in saidgroove. Accordingly, as float 44 rises or falls with'the liquid levelwithin chamber 15, slide rod 55 will" be reciprocally moved by thepivotal movement of lever 46. FIG. 4 illustrates the position of sliderod 55 when chamber 15 is substantially filled with liquid. Ats'uchtimes the cylindrical seat containing seal ring 57 engages theperipheral surface of rod 55 preventing an application of air pressurebetween inlet 51 andoutlet 53, but permitting outlet 53 to be ventedthrough the cylindrical seat containing seal ring 56 to exhaust port 54.

As air or other gases collect within chamber 15, the liquid leveltherein will fall and the weight of float 44 will pivot lever 46 on pin47 and moveslide rod member 55 directionally to the right as' shown inFIGS. 4 and 5. When the slide rod occupies the position of FIG. 5, theseat containing O-ring 57 no longer effects a seal with the surface ofrod 55. Instead, the seat containing O-ring 56 now contacts theperipheral surface of the rod, thereby interrupting fluid communicationbetween outlet 53 and exhaust port 54. Accordingly, theair pressure fromsupply 32 will now be applied through inlet 51, passage 52, outlet 53,passageway 33 and into chamber 31 of air cylinder 25. Referring to FIG.3, piston 29 will be driven downward, compressing spring 43, therebyclosing butterfly valve while simultaneously opening valve member 40.

Operation of the above described metering system and apparatus will nowbe explained in connection with the common difficulties resulting fromentrained air and air which has been trapped in the metering flow line.

It will be initially assumed that all air has been exhausted from aircollecting chamber 15 so that float 44 and valve 34 are positioned asshown in FIG. 4. At this time, chamber 41 of air cylinder is ventedthrough passage 33, outlet 53, passageway 52 and exhaust port 54.Accordingly, spring 43 will force poppet valve 40 against the valveseat' of bypass connector 42, while simultaneously positioning butterflyvalve 20 in an open position, all as shown in FIG. 3. As fluid begins toflow from compartment 12, through air collecting chamber 15, meteringapparatus 16, hose 14 and fill pipe 18, the rate of fluid flow willincrease with the development of a negative liquid head, After a maximumnegative head is established, the rate of fluid flow will slowlydiminish due to the gradual emptying of the truck tank, although it willbe maintained at a relatively high rate determined, in any event, by thecombined effect of both positive and negative liquid heads.

When the level of liquid in compartment 12 nears empty, a vortex may beformed, drawing air into the flow stream, said air being collected inchamber 15. The collection of a sufficient amount of, air to break thenegative head (and the consequent lowering of the liquid level in thechamber) allows float 44 to drop to a point where float arm 45, lever 46and stud 60 acting in groove 59, moves slide rod 55 of valve 34 tothe-position. shown in FIG. 5. High-pressure air from source 32 is nowtransmitted through'control valve 34' and applied to chamber 31 of aircylinder 25, forcing piston 29 sharply downwardly as to partially orcompletely close butterfly valve 20 and restricting the rate of flow orstopping the flow (depending on the design of the valve 20) throughmeter 16. Simultaneously, valve 40 will be moved sharply away from theseat of bypass connector 42 allowing the collected air in chamber 15 toflow through opening 38, connector piece 42 and bypass line 41 to thedischarge side of meter 16. The combined effect of slowing or stoppingthe fluid through butterfly valve 20 and allowing a sufficiently largebubble of air to flow into discharge line 14 breaks the negative liquidhead so that the siphon force thereof is no longer available to induceliquid flowthrough the meter.

As soon as butterfly valve 20 closes, the vortex formed in compartment12 will immediately disappear, and there fore no more entrained air willbe introduced into the flow stream.

Consequently, while poppet valve 40 is maintained open, the liquid levelwill sharply rise in chamber 15 until a sufficient amount of air tobreak the siphon has escaped 6.; from the chamber and float 44 ispositioned at the high end of its stroke. Slide rod 55 will then berepositioned as shown in FIG. 4, thereby venting chamber 31 throughpassage31,'outlet port53, passageway 52 and exhaust port 54. Spring 43'will then sharply move valve 40 into seated engagement with connector42, closing bypass 41. In addition, butterfly valve 20 is sharply'movedinto a fullopen position, permitting the liquid line to fill up withliquid and re-establish the negative head.

When compartment 12 has been completely emptied of fluid and itsinternal flow control valve has been closed, a subsequent refilling ofcompartment 12 for the next delivery will tend to trap air between thecompartment and the inlet opening 36 of collecting chamber 15.Therefore, when the flow control valve is again opened to permit fluiddischarge from the compartment the trapped air will be forced intocollecting chamber 15, whereupon float 44 will drop with the liquid.level in the chamber, producing the same result as above described.Thus, the liquid flow will become partially or completely restricted bybutterfly valve 20 while air is exhausted from the chamber through valve40. This result prevents a negative head from being immediatelydeveloped. However, after the air within collection chamber 15 has beenexhausted in the manner above described, and with the apparatus returnedto the normal operating conditions shown in FIG. 3, the existing highlevel of positive head will create suflicient fluid flow to establish anegative head, resulting in a high rate of flow.

Although various devices have been proposed for use with a gravity fedmetering system, such devices are generally dependent upon a specificdesign of mobile tank truck, the use of vortexbrea-kers or a conditionaltype of operation. Importantly, the apparatus herein described can beeffectively used on conventional mobile tank trucks and tankcompartments, contributing greatly to their use and providing economy ofinstallation. Furthermore, this invention is not limited to meteringsystems where the inlet line between a vehicle compartment and metermust remain full. Metering equipment which depends upon such a conditionof operation do not comply with some regulations and, in any event, arenot permitted by' many users.

Although a preferred embodiment of this invention has been illustratedand described, it is to be understood that various changes may be madewithout departing from the spirit of the invention or the scope of theattached claims, and each of such changes is contemplated. For example,while this disclosure particularly de'scribesone type of control valveand an air cylinder, designed as to operate a normally closed valve in abypass line and a normally open valve in the metering line, thisarrangement of valve operation could be reversed.

What I claim and desire to secure by Letters Patent is:

1. A metering system for high-speed gravity liquid deliveryvehiclest-having an air-brake pressure supply, said system comprising:

(a) a liquid discharge line extending from a storage compartment on thevehicle, said discharge line having a meter therein and a float chamberconnected upstream of said meter for collecting gases, and extendingairtightly a substantial distance downwardly of said meter to provide anegative head when said line is filled with liquid;

(b) a normally open first valve in said discharge line;

(c) a bypass line connecting said float chamber to the discharge side ofsaid meter;

((1) a normally closed second valve connected to said bypass line; and

(e) means for suddenly at least partially closing said first valve andopening said second valve in response to an accumulation of gas in saidfloat chamber just sufficient to cause breaking of said negative headwhen discharged through said bypass line while said liquid is flowing atthe reduced flow rate caused by said at least partial closing of saidfirst valve;

(f) said last-named means including an air-operated (a) a ,liquid flowline having a meter connected therein and a float chamber connectedtherein on the upstream side of said meter, said flow-line extendingairtightly for a substantial distance downward of said meter to create anegative head downstream of said meter when said line is filled withliquid;

(b) a first valve mounted in the discharge end of said float chamber; rI

(c) a bypass line having one end connected to said float chamber and theother end connected to said flow line on the discharge side of saidmeter;

(d) a second valve in said bypass line; and

(e) externally powered means for'simultaneously suddenly at leastpartially closing said first valve and opening said second valve, andvice versa, in response to predetermined liquid levels in said, floatchamber,

2. A metering system for high-speed gravity liquid delivery vehicleshaving an air-brake pressure supply, said system comprising:

(a) a liquid discharge line having a meter therein, said discharge lineextending airtightly a substantial distance downwardly of said meter toprovide a negative said respective liquid levels being sufiicientlyspaced to permit accumulation of enough gases in said float chamber tobreak said negative head when said achcad When aid lin is filled With qcumulated gases are discharged into said flow line (b) means including afloat chamber connected in said upon opening f id second valve, d t itdischarge line upstream of said meter for Collecting unrestricteddischarge of all of said accumulation of gases introduced into saidline; gases; a first Valvfi Connected in said discharge line; (f) saidlast-named means comprising a source of air a yp line Connected betweenSaid float Chamber pressure, air cylinder means for actuating said firstand the discharge side of Said Inetsr; and second valves, and afloat-operated control a second Valve Connected in said yp line; valvehaving a float disposed in said float chamber means including an airCylinder for suddenly for selectively connecting said air cylinder meansto mating said first valve to at least Partially Close and said sourceof air pressure or to an exhaust, said con- Said Second valve to p as50011 as sufficient gas trol valve having an intermediatelost-motionposihas accumulat d in aid fl chamber to Cause the tion to provide atime delay between said connection breaking of said negative head whensaid acc'umula' of said air cylinder means to said exhaust and said lionof gas is discharged downstream of said meter connection thereof to saidsource of air pressure, sufthrough said bypass lin ficient to permit theaccumulation of a substantial (8) means resiliently urging said firstValve to Open 36 amount of gas in said float chamber before the disandSaid Secon valve to 61056; charge thereof through said second valve, andto a passageway With a float-Operated control Valve permit fulldischarge of said accumulated gas before connected between saidair-brake pressure supply and re closing Said second 1 said aircylinder, said control valve having an inlet port connected to saidpressure supply, an outlet con- 40 References Cit d nected to said aircylinder, an exhaust port, and a movable valve member for selectivelyconnecting UNITED STATES PATENTS either said inlet port and outlet portor said outlet 1,622,715 3/ 1927 HaW hHr 73200 port and said exhaust, orclosing said outlet port off 2,093,952 9/ 1927 Br b k r 73200 Xaltogether, and a float disposed within said float 2,103,020 12/193'7rmcn 73-200 X chamber for operating said movable valve member 2,318,2645/1943 7 Smith u 73 2()() in response to the liquid level in said floatchamber, 3,040,573 2 Berck 73-200 the movement of said valve memberthrough the 3,040,574 9 2 Berck 73--200 zone where said outlet port isclosed off altogether 3,081,627 1963 Reed et a1. 73-20O 3,135,114 6/1964Granberg 73-200 being sufficiently long to allow unrestricted dischargeof the entire said gas accumulation in one direction of movement andaccumulation of said sufficient gas accumulation in the other direction.3. Apparatus for use in a high-speed gravity liquid discharge meteringsystem to prevent registration of gases, comprising:

OTHER REFERENCES German printed application, 101,561, September 1957.

RICHARD C. QUEISSER, Primary Examiner.

EDWARD D. GILHOOLY, Assistant Examiner.

